Image display apparatus, method, and program for automotive vehicle

ABSTRACT

In image display apparatus, method, and program for an automotive vehicle, a surrounding of the vehicle is photographed, a plurality of display images are generated from a photographed data supplied from a photographing section, viewing points of the respective display images and looking down angles thereof being different from one another, one of the images generated is displayed through a display, and the display image generated and displayed through the display is switched to another one of the generated display images.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to image display apparatus, method, andprogram for an automotive vehicle which are capable of displaying thevehicle and a surrounding of the vehicle viewed from an upper skythrough a looking down angle that the vehicle driver desires.

2. Description of the Related Art

A Japanese Patent Application First Publication No. Heisei 11-151975published on Jun. 8, 1999 exemplifies a previously proposed imagedisplay apparatus for an automotive vehicle in which an imagesurrounding the vehicle is photographed by a camera equipped within thevehicle is displayed within a vehicular passenger compartment in orderto assist an operation of the vehicle during an entrance of the vehiclein a parking lot or garage.

It is possible to display directly the image photographed by the camerathrough a display in the previously proposed display apparatus. However,a viewing point of the camera is transferred to an upper sky above thevehicle. Then, a top view image looking down to the vehiclesubstantially vertically is tried to be displayed on the display. Thetop view image displays the vehicle substantially vertically from theupper sky. Hence, in a case where the vehicle parks a predeterminedparking space, it is advantageously easy to recognize a positionalrelationship between the parking space and the vehicle.

SUMMARY OF THE INVENTION

However, the top view image is an image whose viewing point of thecamera equipped within the vehicle is moved to the upper sky over thevehicle, a distortion due to a deviation of the viewing point isincluded. In addition, in a case where a three-dimensional vehicle witha height is projected onto a mounting plane (ground surface and soon) ofthe vehicle, a distortion in a height direction becomes remarkable andthere is a disadvantage that a stereoscopic sense of distance isdifficult to be grasped. Especially, in a case where the driver drivesthe vehicle avoiding such obstacles as other vehicle, motor bicycle, orbicycle, there is an inconvenience that a position of any obstacle isnot easily recognized from the top view image.

That is to say, in a case where the vehicle is parked at a predeterminedparking space while confirming the position of the vehicle, the top viewimage is appropriate. However, the vehicle is advanced avoiding acollision against an obstacle while measuring a three-dimensional(stereoscopic) distance from the obstacle to the vehicle. In thissituation, the display of the top view image is inappropriate. Asdescribed above, the display of only the top view image cannotsufficiently assist a driver's manipulation on the vehicle.

Furthermore, in the previously proposed image display apparatus, whenthe image of the camera as viewed from the exact upper sky isperspectively transformed into the image viewed from the viewing pointhaving a height near to an infinity, the image is not transformed to theimage viewed from the right upper sky. Consequently, a distorted imageis displayed.

It is, therefore, an object of the present invention to provide imagedisplay apparatus, method, and program for an automotive vehicle inwhich the display of one of a plurality of display images, viz., a topview image and that of a bird's eye view image are switched therebetweento display the image suitable for the assistance of the driver'smanipulation and which are, preferably, capable of displaying the imagesurrounding the vehicle viewed from the upper sky without imagedistortion.

In image display apparatus, method, and program according to the presentinvention, at least one of a top view (or called, a plane view) imageapproximately vertically looking down to the vehicle from a firstviewing point located above the upper sky just above the vehicle and abird's eye view (or called, a perspective view) slightly obliquelylooking down the vehicle from a second viewing point located above theupper sky above the vehicle is generated and the top view image andbird's eye view image are switched therebetween and displayed inaccordance with a running information related to a received vehicularrunning situation. It is noted that the running information used in thewhole specification is an information related to a direction towardwhich the vehicle runs, viz., the vehicle runs in a forward direction,the vehicle runs in a backward direction, or the vehicle stops, aninformation related to a history of the direction toward which thevehicle moves, viz., the vehicle stops after the vehicle runs in theforward direction or the vehicle stops after the vehicle runs in thebackward direction, an information on whether the vehicle is running ata speed equal to or higher than a predetermined value of speed, or anyother information related to the vehicular running situation. The imagedisplay apparatus, method, and program according to the presentinvention selectively displays the image suitable for assisting theoperation of the vehicle driver according to such a running informationas described above. That is to say, when the vehicle is running in thebackward direction, there is a high possibility of manipulating thevehicle for the vehicle to be parked by the driver. At this time, thetop view image to objectively display a positional relationship betweena predetermined parking space and vehicular positional relationship isdisplayed. On the other hand, when the vehicle is running in the forwarddirection, there is a high possibility of driving the vehicle so as toavoid a collision against an obstacle such as another vehicle. Hence,the bird's eye view image easy to grasp a stereographic sense ofthree-dimensional distance is displayed. In this way, since the displayof one of the top view image and the bird's eye view image is switchedaccording to the running situation of the vehicle, one of the imagesappropriate for the driver's vehicular manipulation assistance can bedisplayed.

According to a first aspect of the present invention, there is providedan image display apparatus for an automotive vehicle, comprising: aphotographing section that photographs a surrounding of the vehicle; adisplay image generating section that generates a plurality of displayimages from a photographed data supplied from the photographing section,viewing points of the respective display images and looking down anglesthereof being different from one another; a display section throughwhich one of the images generated by the display image generatingsection is displayed; and a display image switching section thatswitches the display image generated by the display image generatingsection and displayed through the display section to another one of thedisplay images generated thereby.

According to a second aspect of the present invention, there is providedan image display apparatus for an automotive vehicle, comprising: aphotographing section that photographs a surrounding of the vehicle; adisplay image generating section that generates a plurality of displayimages from a photographed data supplied from the photographing section,viewing points of the respective display images and looking down anglesthereof being different from one another; a display section throughwhich one of the images generated by the display image generatingsection is displayed; a display image switching section that switchesthe display image generated by the display image generating section anddisplayed through the display section to another one of the displayimages generated thereby; a surrounding vehicle detecting section thatdetects a surrounding vehicle to the vehicle from the photographed data;and a pseudo vehicular image drawing section that draws a pseudovehicular image, and wherein the display image generating sectiongenerates the images with which the pseudo vehicular image issynthesized.

According to a third aspect of the present invention, there is providedan image display method for an automotive vehicle, comprising: receivingphotographed data on a surrounding of the vehicle; receiving a runninginformation related to a vehicular running situation; generating aplurality of display images from the photographed data, viewing pointsof the respective display images and looking down angles thereof beingdifferent from one another; displaying one of the generated images; andswitching the display image generated and displayed through a display toanother one of the generated display images in accordance with therunning information related to the vehicular running situation.

According to a fourth aspect of the present invention, there is providedan image display method for an automotive vehicle, comprising:photographing a surrounding of the vehicle; generating a plurality ofdisplay images from a photographed data supplied at the photographing ofthe surrounding of the vehicle, viewing points of the respective displayimages and looking down angles thereof being different from one another;displaying one of the generated images; switching the display imagegenerated and displayed through a display to another one of thegenerated display images; detecting a surrounding vehicle to the vehiclefrom the photographed data; and drawing a pseudo vehicular image, andwherein the images with which the pseudo vehicular image is synthesizedare generated.

According to a fifth aspect of the present invention, there is providedan image display program for an automotive vehicle, comprising: having acomputer mounted in the vehicle receive a photographed data on asurrounding of the vehicle through at least one camera disposed on thevehicle; receive a running information related to a vehicular runningsituation; switch a position of a predetermined viewing point at anupper sky above the vehicle and a looking down angle from the viewingpoint; generate a display image which displays the vehicle from thepredetermined viewing point with the predetermined looking down angle onthe basis of the received photographed data; and execute an output ofthe display image to a display.

This summary of the invention does not necessarily describe allnecessary features so that the invention may also be a sub-combinationof these described features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of an image display apparatus foran automotive vehicle in a first preferred embodiment according to thepresent invention.

FIG. 2 is a first explanatory view for explaining a transformationprocess from a top view image to a bird's eye view image.

FIG. 3 is a second explanatory view for explaining the transformationprocess from the top view image to the bird's eye view image.

FIG. 4 is a general operational flowchart for explaining an operation ofthe image display apparatus in the first embodiment according to thepresent invention.

FIG. 5 is an operational flowchart for explaining an operation ofswitching a display image on a display of the image display apparatus inthe first preferred embodiment according to the present invention.

FIG. 6 is a display-example of a top view image selected at a step S631Ashown in FIG. 5.

FIG. 7 is a display example of a bird's eye view image selected at astep S632B shown in FIG. 5.

FIG. 8 is a display example of a superposition of an arrow mark graphicdata indicating a direction toward which the vehicle moves on the topview image shown in FIG. 6.

FIG. 9 is a display example of a superposition of the arrow mark graphicdata indicating the direction toward which the vehicle moves on thebird's eye view image shown in FIG. 7.

FIG. 10 is a display example of the bird's eye view image selected at astep S671B of FIG. 5.

FIG. 11 is a display example of the top view image selected at a stepS672A shown in FIG. 5.

FIG. 12 is an operational flowchart for explaining another operation ofswitching the display image on the display as an alternative to thefirst embodiment.

FIG. 13 is an operational flowchart for explaining a viewing pointswitching function of a switching section in a case of the image displayapparatus in a second preferred embodiment according to the presentinvention.

FIG. 14 is a functional block diagram of the image display apparatus forthe automotive vehicle in a third preferred embodiment of the imagedisplay apparatus according to the present invention.

FIG. 15 is an explanatory view indicating a plurality of cameras locatedon a surrounding section of the vehicle.

FIG. 16 is an operational flowchart for explaining a vehicularsurrounding image display program executed in the image displayapparatus in the third preferred embodiment according to the presentinvention.

FIG. 17 is a display example of an image photographed by a cameralocated at a rear right side of the vehicle in a case of the thirdembodiment shown in FIG. 14.

FIG. 18 is a display example of an image in which a plurality ofvehicular surrounding images photographed by a plurality of cameras areperspectively transformed into the image with an upper portion of thevehicle as a viewing point and the perspectively transformed image issynthesized with a pseudo vehicular image of the vehicle in the thirdembodiment.

FIG. 19 is a display example of an image in which edges in amonochromatic (black-and-white) image are emphasized.

FIG. 20 is a display example of an image in which a pseudo vehicularimage of another vehicle is overwritten and synthesized on the vehicularsurrounding image.

FIG. 21 is an explanatory view representing a tire wheel detectingpattern to carry out a pattern matching on the vehicular surroundingimage in a case of a fourth preferred embodiment according to thepresent invention.

FIG. 22 is an explanatory view for explaining a method of carrying out apattern matching on the image photographed by a camera.

FIG. 23 is an explanatory view for explaining a method of detecting atire wheel on the vehicular surrounding image.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will hereinafter be made to the drawings in order tofacilitate a better understanding of the present invention.

First Embodiment

A vehicular image display apparatus 100 in a first preferred embodimentaccording to the present invention is an apparatus in which an image ofan automotive vehicle and a surrounding of the vehicle looking down froma viewing point located at an upper sky above the vehicle is displayedon a display 4 installed within a vehicular passenger compartment. FIG.1 shows a block diagram of the image display apparatus in the firstpreferred embodiment according to the present invention. FIGS. 2 and 3show explanatory views for explaining a transform process from a topview image (a whole vehicular image, or plan view image) into a bird'seye view image (FIG. 2 corresponds to a Y-axis direction transformationprocess and FIG. 3 corresponds to an X-axis direction transformationprocess). As shown in FIG. 1, in the first preferred embodiment, imagedisplay apparatus 100 includes: a plurality of cameras (1 a, 1 b, - - -) photographing the vehicle and the surrounding of the vehicle; adisplay image generating (producing) section 2 which generates displayimages from the photographed data photographed by cameras 1 a, 1b, - - - ; and a display 4 which displays the prepared display image.Camera 1 a, 1 b, - - - , disposed at an outside of the vehicle tophotograph the surrounding of the vehicle and to obtain the photographdata. An arrangement of cameras 1 a, 1 b, - - - and the number ofcameras 1 a, 1 b, - - - are, specifically, not limited. Cameras 1 (1 a,1 b, - - - ) may be constituted by optical cameras having lens systems.In the first embodiment, digital cameras having CCD (Charge CoupledDevice) devices are adopted as surrounding photographing cameras 1 a and1 b. The photographed data are supplied to display image generatingsection 2.

Image generating section 2 generates the bird's eye view (perspectiveview) on which the vehicle is projected from a predetermined viewingpoint located at an upper sky above the vehicle on the basis of thephotographed data retrieved (received) from cameras 1 a, 1 b, - - - . Inthis embodiment, the term of the top view image means an image lookingdown substantially vertically to the vehicle from a predeterminedviewing point (a first viewing point) located at the upper sky justabove the vehicle. On the other hand, the bird's eye view means aperspective view image looking down of the vehicle in an obliquedirection from the upper sky above the vehicle. Specifically, the bird'seye view image is an image looking down of the vehicle through a lookingdown angle from a predetermined viewing point (a second viewing point)of the upper sky above the vehicle. This second viewing point is a pointof the first predetermined point moved in a forward direction or arearward direction with respect to a vehicular movement direction.

Display image generating section 2 includes a microcomputer having: aCPU (Central Processing Unit); ROM (Read Only Memory); and RAM (RandomAccess Memory). That is to say, the ROM stores a program or firmwaretherein. The CPU functions as display image generating section 2 byexecuting the program stored in the ROM. The RAM serves as a memory(storing) section 30. It is of course that the CPU, the ROM, and RAM maybe constituted by a logic circuit(s). Specifically, display imagegenerating section 2 is provided with storing section 30. Furthermore,this storing section 30 includes a region storing camera information 31,a region storing coordinate transformation equation 32, and a regionstoring a graphic data 33. This camera information 31 is an informationnecessary when the whole image is synthesized from the photographed databy means of a synthesizing section 21. The camera information 31includes an information on mounting positions, photographing directions,and photographed angles of cameras 1 a, 1 b, - - - , the lensinformation, and CCD device related information. Coordinatetransformation equation 32 is an equation required for the coordinatetransforming section 22 to transform the top view image into the bird'seye view image. This transformation equation includes the informationrelated to the top view image, the position of the viewing point of thebird's eye view image, the looking down angle from the viewing point, aposition of a projected plane (including an angle between the projectionplane and mounted plane of the vehicle), and the information requiringthe other transformation or required information to derive coordinatetransformation equation 32. Graphic data 33 is an image information inan arrow mark shape indicating visually the direction toward which thevehicle moves, the image information expressing stereographically andvisually the vehicle from the predetermined viewing point through apredetermined projection angle, and an image information expressingstereographically or flatly a reference line net. Storing section 30previously stores arrow mark graphic data k, k′ in an arrow marked formrepresenting the direction toward which the vehicle moves, vehiculargraphic data p, p′ representing stereographically the vehicle inaccordance with the viewing point and projection plane, and a top viewimage grid line g or a bird's eye view image grid line g′ therein.

In addition, display image generating section 2 includes: a synthesizingsection 21 which synthesizes the top view image substantially verticallylooking down the vehicle from the first viewing point located at theupper sky above the vehicle according to a plurality of photograph dataretrieved (received) from cameras 1 a and 1 b; a transforming section 22that transforms the top view image described above into the bird's eyeview looking down the vehicle through a predetermined looking down anglefrom the second viewing point with the first viewing point of the topview image moved into a front area of the vehicular forwarding directionor a rearward area of the forward direction of the vehicle; and asuperposing section 23 that superposes the graphic data 33 on the bird'seye view image transformed by transforming section 22. Display imagegenerating section 2 determines whether the top view image should betransformed into the bird's eye view image. In order to switch thedisplay image between the bird's eye view image and the top view image,image generating section 2 includes: a switching section 24 whichcontrols a transformation process of transforming section 22; a commandaccepting (reception) section 25 which receives a vehicle driver'scommand from an external manual switch 5 and transmits the correspondingcommand signal to switching section 24; and a running informationreceiving section 26 which transmits the running information receivedfrom an external running situation detecting section 6 to switchingsection 24.

In other words, manual switch 5 receives a command on the display of theimage issued by the vehicle driver. Such a command as described aboveincludes a switching command on the display image such as “display thetop view image”, “display the bird's eye view image”, and “display theimage with the viewing point as A and the looking down angle as B” and aswitch command of the display mode such as “display the bird's eye viewimage during the vehicular run in the forwarding direction and displaythe top view image during the vehicular run in the backward direction”and “display the bird's eye view image during the vehicular run in thebackward direction and display the top view image during the forwarddirection of the vehicle”. The form of the switching command is notlimited to this.

Running situation detecting section 6 retrieves (receives) the runninginformation related to the running situation of the vehicle. The runninginformation in this embodiment is an information related to an operationof a shift position (automatic transmission select lever) of the vehicleand its operation history and uses a shift position signal detected by ashift position detecting section 61. According to the shift positionsignal, the forwarding or reversing of the vehicle and a history of theforwarding direction and rearward direction such as a case where thevehicle stops after the vehicle runs in the forwarded direction or wherethe vehicle is stopped after the vehicle runs in the backward directioncan be retrieved (received).

Herein, a more detailed explanation of the structure and function ofdisplay image generating section 2 will be described below. Displayimage generating section 2 includes: synthesizing section 21;transformation (transforming) section 22; switching section 24; andsuperposing section 23, as shown in FIG. 1.

Synthesizing section 21 retrieves (obtains) each photograph dataphotographed by means of each camera 1 a, 1 b, - - - . Synthesizingsection 21 synthesizes the photographed data in accordance with aphotograph range of each camera 1 a, 1 b, - - - into a single integratedtop view image representing the vehicular surrounding. This top viewimage is an image approximately vertically looking down to the vehiclefrom the predetermined first viewing point located at the upper skyabove the vehicle. In this case, synthesizing section 21 reads thecamera information 31 from storing section 30 and synthesizes the topview image on the basis of the camera information 31 and photographeddata. It is noted that the viewing point of the previously set top viewimage is not limited specifically provided that it is located at anupper sky above the vehicle.

Transforming section 22 transforms the top view image synthesized bysynthesizing section 21 into the bird's eye view image. The bird's eyeview image is an image looking down to the vehicle through apredetermined looking down angle from the second viewing point locatedabove the upper sky of the vehicle. The position of the second viewingpoint on the bird's eye view image is not limited specifically. However,the position of the second viewing point is a position at which aforwarding direction or rearward direction of the vehicle is moved withrespect to the first viewing point of the top view image. In addition,the projection plane over which the looked down vehicle is projected hasa predetermined angle α (0<α≦90°) with respect to the vehicular mountingplane and is preferably a plane having a gradient with respect to avehicular mounting plane (road surface, ground surface, and parkingplane). This is because a distortion in a height direction of thevehicle in the bird's eye view image is relieved. Angle α is not limitedbut is determined according to the position of the viewing point. Thisangle α is determined according to the position of the viewing point. Inthe first embodiment, a plane perpendicular to a looking down directionfrom a predetermined viewing point is the projection plane.Specifically, if the looking down direction from a predetermined viewingpoint is an angle θ with respect to the mounting plane of the vehicle,the projection plane has an angle of α=90°−θ with respect to themounting plane of the vehicle.

It is noted that an example of transformation process from the top viewimage to the bird's eye view image by means of transformation section 22will be described with reference to FIGS. 2 and 3.

In this transformation process example, the top view image (an imagelooking down to the vehicle from the upper sky above the vehicle)synthesized, with the predetermined position of the upper sky above thevehicle as a viewing point (first viewing point), is transformed intothe bird's eye view image (an image looking down through a predeterminedlooking down angle) with another predetermined point on the upper skyabove the vehicle (the image looked down through the predeterminedlooking down angle from the second viewing point).

In order to transform an arbitrary point B on the coordinate (uppersurface viewing point) of the top view image shown in FIG. 2 into thepoint C on the coordinates of the bird's eye view image, a relationshipbetween points of the top view coordinates and of the bird's eye viewcoordinates will be introduced.

First, the coordinate transform in the Y-axis direction will bedescribed with reference to FIG. 2. The axis denoted by Y is a Ycoordinate axis at the top view coordinates. A point A shown in FIG. 2represents a position of the viewing point of the bird's eye view image.In FIG. 2, h denotes a height in the top view coordinate of the viewingpoint and θ denotes a looking down angle from the viewing point.

An axis y denoted by y is a y coordinate axis in the bird's eye viewcoordinates, prescribing the y axis of the projection plane (a plane onwhich the bird's eye view is viewed) projected with the top view imagetransformed. The projection plane is set at a position away from apredetermined distance DS from the viewing point A. Distance DS isdetermined according to a magnitude of the display image displayed via adisplay 4.

A y coordinate value C(y) at a point C projected in the bird's eye viewcoordinates C(y) is calculated from arbitrary point B on the top viewcoordinate system as follows:C(y)=−DS·tan θ−DS·tan ω  (1)=−DS(tan θ+tan ω)  (2).

DS: a distance from viewing point A to a projection plane, θ denotes anangle looking down from viewing point A, and ω denotes an angle formedbetween a line of sight looked down from viewing point A through anangle of θ to a line segment AB.

On the other hand, Y coordinate value B(Y) at an arbitrary point C onthe top view coordinates is as follows:B(Y)={h/sin(θ+ω)}·(cos ω/cos θ)+C  (3).In equation (3), h denotes a height of each camera, a denotes a marginof the image (preset value).

If equation (3) is arranged, the following equation (4) is satisfied:B(Y)={h/(tan θ+tan ω)}·(1/cos ²θ)+c  (4).

From equations (1) and (4), the following equation is obtained:B(Y)=(−h·DS/cos ²θ)·(1/C(y))+c  (5).

It is noted that, ifb=h·DS/cos ²θ  (6),equation (5) can be arranged as follows:B(Y)=(−b/C(y))+c  (7).

A mutual transformation between point B (Y) on the top view image andpoint C(y) on the bird's eye view image can be obtained.

Next, the transformation of the coordinates in the X axis direction willbe explained with reference to FIG. 3.

An axis denoted by X is an X coordinate axis in the top view coordinateof the top view image. In addition, an axis denoted by x is an xcoordinate axis in the bird's eye view image. Now, x coordinate valueC(x) of a projection point C onto which an arbitrary point B on the topview coordinate is projected on the bird's eye view coordinate isderived. A ratio between a distance d from viewing point A to an X axisof the top view coordinate including arbitrary point B and X coordinatevalue (top view coordinate) of arbitrary point B is equal to the ratiobetween DS and x coordinate value C(x) of projected point C. Hence,B(X)/d=C(x)/DS  (8).

It is noted that d corresponds to a distance between viewing point A ofFIG. 2 and a point D of FIG. 2. This distance denoted by AD is the sameas the distance from arbitrary point B and point E and is expressed asd=(B(Y)−c)cos θ. If d is substituted into equation (8), equation (8) canbe expressed as:B(X)=(cos θ/DS)·C(x)·(−b/C(y)) and B(X)=−b·(cosθ)/DS)·(C(x)/C(y))  (10).Herein, ifa=b·(cos θ/DS), B(X)=−a·(C(x)/C(y))  (11).

Thus, arbitrary point B(X) on the top view coordinate can be transformedto port C(x) on the bird's eye view. Then, in each constant of a, b, andc, specific numerical values are substituted and C(x, y) in the bird'seye view coordinate is derived from B(X, Y).

In accordance with a determination by switching section 24 that thebird's eye view image should be displayed, the top view image istransformed into the bird's eye view image and supplied to superposingsection 23. On the other hand, in a case where switching section 24determines that the top view image is to be displayed, transformingsection 22 supplies the top view image directly to the superposingsection 23 without coordinate transformation. It is of course that thetop view image may be supplied from synthesizing section 21 tosuperposing section 23 without intervention of transforming section 22.

Next, switching section 24 will be described in more details. Switchingsection 24 determines a formation of the displayed image which displaysin accordance with the running situation of the vehicle and controls thetransformation process of transforming section 22 to switch the displayof the image. That is to say, in the case where the top view image isdisplayed, the top view image synthesized by synthesizing section 21 isnot transformed into the bird's eye view image but is supplied directlyto superposing section 23 to display the top view image through display4. On the other hand, in the case where the bird's eye view image isdisplayed, transforming section 22 transforms the top view image intothe bird's eye view image and the bird's eye view image is displayed ondisplay 4 via superposing section 23.

Switching section 24 retrieves (accepts) the running information viarunning information receiving section 6 when the switching process iscarried out. The running information includes a running informationrelated to a vehicular forwarding direction retrieved from shiftposition sensor 61 and the running information related to a vehicularrunning velocity (received) retrieved from vehicle velocity sensor 62.In a case where the image to be displayed is switched in accordance withthe running direction, the image is switched according to whether thevehicle is running in the forward direction or in the backwarddirection, or according to a history of whether the vehicle has stoppedafter the vehicle has run in the forwarded direction or the vehicle hasstopped after the vehicle has run in the backward direction or any otherhistory of vehicular run and stop. In addition, in a case where theimage to be displayed in accordance with the running velocity (vehicularvelocity) is switched, the image is switched depending upon whether therunning velocity of the vehicle is equal to or higher than apredetermined value of S or lower than S. The predetermined value of Sis stored into storing section 30. The predetermined value of S is notspecifically limited if the running situation of the vehicle can bedetermined. For example, in a case where the vehicle runs at a speedrange of 5 Km/h through 15 Km/h, it is predicted that the driver drivesthe vehicle confirming the positional relationship of the vehicle andsurrounding the vehicle. In this case, it is preferable to display thetop view image. From these points of view, the predetermined value S canbe set. In this case, switching section 24, in principle, the top viewimage is displayed if 5 Km through 15 Km/h>(or ≧) S and the bird's eyeview image is displayed if 5 Km through 15 Km≦(or <) S. To achieve this,switching section 24 performs switching. In this determination, equal toor larger (≧), larger than (>), less than (<), and equal to or less than(≦) are within a range of a design matter. It is of course that thebird's eye view image may be displayed when 5 Km through 15 km>(or ≧S)in accordance with the driver's command and the top view image may bedisplayed when 5 Km through 15 Km≦(or <) S. The predetermined value of Sin this embodiment is set to 10 Km. Then, in principle, in a case where10 Km>S, the top view image is displayed. In a case where 10 Km≦S, thebird's eye view image is displayed. In this embodiment, the relationshipbetween the predetermined value S and actual running speed is determinedby switching section 24. Running information receiving section 26compares the detected running velocity with predetermined value S, asignal indicating the result of the comparison may be supplied toswitching section 24 as the running information.

In this way, switching section 24 carries out the switching of thedisplay image in accordance with the running situation detected by therunning situation detecting section 6 of the vehicle. Hence, theswitching of the image in a direct correspondence with the driver'smanipulation of the vehicle and the running situation of the vehicle canbe achieved.

Switching section 24 includes: an image switching function 241 whichswitches the display of the top view image and the display of the bird'seye view image; and a viewing point switching function 242 whichswitches the viewing point of the image and the looking down angle fromthe viewing point. In this embodiment, image switching function 241 isactivated. It is noted that viewing point switching function 242 will bedescribed later in the second preferred embodiment. According to imageswitching function 241 switches the top view image display when viewingthe vehicle substantially vertically from a preset viewing point and thedisplay of the bird's eye view image looking down to the vehicle throughthe predetermined looking down angle and with a preset viewing point.Since each of the top view image generated, the viewing point of thebird's eye view image, and the looking down angle thereof is preset,transforming section 22 may transform the top view image by readingcoordinate transformation equations 32 from storing section 30 inaccordance with the viewing point and looking down angle. A time ittakes to process the generation of the bird's eye view image is not solong and the display switching can be made at a high speed.

The determination of switching of the display image by means ofswitching section 24 is carried out on the basis of the runninginformation retrieved (received) by running information receivingsection 26. The running information is detected by means of on-vehiclerunning situation detecting section 6 which is deemed to be an externaldevice. Running situation detecting section 6 includes: shift positionsensor 61 which detects a manipulation and a manipulation history of thevehicle; and vehicular velocity sensor 62 which detects the velocity ofthe vehicle. Shift position sensor 61 detects whether the vehicle isforwarding, reversing, or is stopped according to the position of theshift lever of the transmission and detects the history of the vehicularforwarding direction according to the history of the shift lever (stopsafter the vehicle is forwarding and stops after the vehicle isreversed). In other words, the shift position signal according to thepresent invention includes the information related to the manipulationof the shift position and its operation (manipulation) history. Therunning direction of the vehicle and history of the running direction ofthe vehicle can be retrieved (received) from shift position sensorsignal. Vehicle velocity sensor 62 detects the running velocity of thevehicle from a speedometer equipped within the vehicle. It is possibleto supply the running velocity received from running informationretrieving section 26 directly to switching section 24. However, upondetermination of a magnitude relationship between the running velocityof the vehicle and predetermined value S and the result of determinationmay be supplied to switching section 24, as described above.

Running information receiving section 26 receives the vehicular runninginformation from shift position sensor 61 or vehicle velocity sensor 62and supplies this information to switching section 24. In thisembodiment, although running information receiving section 6 isinstalled in addition to switching section 24, it is possible to haveswitching section 24 also serve as the function of running informationreceiving section 6.

Switching section 24 can be switched between the display of the top viewimage and that of the bird's eye view image on the basis of the vehicledriver issued command received in addition to the running information.Command reception section 25 accepts the driver issued command. Thiscommand is inputted via manual switch 5. The form of the vehicle driverissued command is not specifically limited to this. Such specifying anoperation form command as “display the top view image when the vehicleruns in the forward direction” or as “display the bird's eye view imagewhen the vehicle runs in the backward direction”. It is preferable toset a higher priority in the switching process based on the acceptedcommand by command reception section 25 than the switching process basedon the running situation. In this embodiment, both of the runninginformation retrieving section 26 and the command accepting section 25are provided. In the usual practice, the switching process based on therunning information is carried out. If the command issued from thedriver via manual switch 5 is accepted, the switching process based onthe vehicle driver issued command is carried out. Superposing section 23superposes graphic data 33 on the accepted bird's eye view image(three-dimensional graphic data of the vehicle including the graphicdata of the arrow mark representing the direction toward which thevehicle moves and the grid line). Storing section 30 previously storesvehicular graphic data p. p′ on the basis of which an appearance of avehicle is projected from a predetermined viewing point, arrow markgraphic data k and k′ indicating the direction toward which the vehiclemoves, and grid line g, g′ indicating a reference line net of thedisplayed image as graphical data 33 therein. When the superpositionprocess is carried out, superposing section 23 reads predeterminedgraphic data 33 from storing section 30. When the superpositionprocessing is carried out, predetermined graphic data 33 is read fromstoring section 30 and is superposed on a display image (top view imageor bird's eye view image). By superposing graphic data 33, the image ofthe vehicle and its surrounding are displayed stereographically. Thedriver can easily grasp the situation surrounding the vehicle.Especially, vehicular graphic data p, p′ are image data representing thevehicle stereographically in accordance with a predetermined viewingpoint or a combination of the predetermined viewing point with thepredetermined projection plane.

Vehicular graphic data p, p′ stored for each combination of this viewingpoint and the projection plane are superposed with viewing point and/orthe projection plane as a reference. A dead angle of each camera 1results in a fragment of the photograph data and the fragment of theimage of either the top view image or bird's eye view generated on thebasis of this photographed data. The superposed vehicular graphic datap, p′ compensate for this fragment. In other words, a shadow is involvedin vehicular graphic data p, p′ viewed toward the vehicle from thepredetermined viewing point. If a part of the image at which the imageis fragmented due to the presence of the dead angle of each camera 1 ishidden by shadows of the vehicular graphical data p, p′, no problem ofthe fragment of the image occurs in the displayed image. As describedabove, the superposed vehicular graphic data p, p′ can compensate forthe fragment of the image which would appear on the image of thesuperposed vehicular graphical data p. p′. Thus, no fragment image canbe generated.

In addition, vehicular graphic data p′ and bird's eye view imageconstituting the display image has no distortion in the image if theyare superposed since these are images projected from the same viewingpoint into the same projection plane. Furthermore, since the wholevehicle is expressed three-dimensionally according to vehicular graphicdata p, p′, the user is easy to grasp the vehicle situation with astereographic sense of distance and is easy to confirm a part of thevehicle which is near to the ground which is easy to become the deadangle of each camera 1 can more accurately be displayed.

It is noted that, in this embodiment, as described above, synthesizingsection 21, transforming section 22, and superposing section 23installed in image generating section 2 execute such processes as thegeneration of top view image, the transformation into the bird's eyeview image, and the superposition of the graphic data. However, an orderof processes is not limited to this. For example, display imagegenerating section 2 can integrally process the synthesis process ofsynthesizing section 21 and transforming process of transforming section22. In addition, display image generating section 2 may integrallyprocess the synthesis process of synthesizing section 21, superpositionprocess of superposing section 23, and/or transformation process ofsuperposing section 23. It is of course that it is possible to carry outthe synthesis process, the transformation process, and the superpositionprocess integrally.

An operation of the image display apparatus in the first embodimentaccording to the present invention will be described with chiefreferences of flowcharts of FIGS. 4 and 5 and display examples of FIGS.6 through 11.

FIG. 4 shows an operational flowchart for explaining an operation ofimage display apparatus 100 in the first preferred embodiment. FIG. 5shows a detailed flowchart for explaining a switching operation of animage to be displayed. FIG. 6 shows a display example of a top viewimage selected at a step S631A in FIG. 5. FIG. 7 shows a display exampleof a bird's eye view image selected at a step S632B shown in FIG. 5.FIG. 8 shows a display example of arrow mark graphic data k representingthe direction toward which the vehicle moves and which is superposed (orsuperimposed) on the top view image shown in FIG. 6. FIG. 9 shows adisplay example of an arrow mark graphic data k′ representing thedirection toward which the vehicle moves and which is superposed on thebird's eye view image shown in FIG. 7. FIG. 10 shows a display exampleof the bird's eye view image selected at a step S671B of FIG. 5. FIG. 11shows a display example of the top view image selected at a step S672Ashown in FIG. 5.

As shown in FIG. 4, if vehicular image display apparatus 100 isactivated at a step S1, the plurality of cameras 1 (1 a, 1 b, - - - )photograph the respective images of vehicle and vehicular surrounding ata step S2. At a step S3, cameras 1 supply the photographed data to imagegenerating section 2. At a step S4 of FIG. 4, synthesizing section 21synthesizes the top view image surrounding the vehicle on the basis ofthe photographed data and camera information 31 read from storingsection 30. At a step S5 of FIG. 4, running information receivingsection 26 receives the running information from the running situationdetecting section 6 before or after the synthesis process by thesynthesizing section 21. The received running information is supplied toswitching section 24. Switching section 24 switches the image displayedon display 4 into either the top view image or bird's eye view image inaccordance with the running information at a step S6 of FIG. 4. At thetime of switching the displayed image, image switching function 241 orview point switching function 242 is activated. In this embodiment,image switching function 241 activated to switch the display byselecting either of the top view image or the bird's eye view image at astep S7 of FIG. 4. Image switching function 241 selects either the topview image or the second view image at a step S8 of FIG. 4 in accordancewith the vehicular running information. This selection and switchingoperations will be described later with reference to FIG. 5.

If image switching function 241 of switching section 24 selects the topview image (step S9), it is not necessary to carry out thetransformation process from the top view image to the bird's image andimage switching function 241 does not command the transformation processfrom the top view image to transformation section 22. In this case, thetop view image synthesized by synthesizing section 21 is directlysupplied to superposing section 23. Thus, graphical data are superposedon synthesizing section 21 at a step S12 in FIG. 4. The top view imageon which the graphical data are superposed is displayed through display4. On the other hand, if image switching function 241 of switchingsection 24 selects the bird's eye view image in place of the top viewimage at a step S9, transformation section 22 reads coordinatetransformation equation 33 of the bird's eye view image from the storingsection 30 at a step S10 of FIG. 4. Transforming section 22 refers tothe coordinate transformation equations 32 read from storing section 30and transforms the top view image into the bird's eye view image at astep S11 of FIG. 4. The transformed bird's eye view image is supplied tosuperposing section 23. Then, the graphic data are superposed on bird'seye view-image at step S12. The bird's eye view image onto which thegraphical data is superposed is displayed through display 4 at step S14.

Next, a switching operation of the displayed image will be describedbelow with reference to FIG. 5.

The operation with reference to FIG. 5 corresponds to a subroutine toswitch the image displayed at step S6 described in FIG. 4. Switchingsection 24 in this embodiment switches the image displayed on the basisof the running information received by running information receivingsection 26 and switches the image to be displayed on the basis of theswitching command from the vehicle driver which is accepted by commandinformation (acceptance) section 25. Then, if switching section 24 isactivated to switch the image to be displayed at a step S600, commandreception (acceptance) section 25 determines whether the switch commandis inputted by the vehicle driver via manual switch 5 (step S610). If noswitch command from the driver is issued, the routine goes to a stepS630. At step S630, switching section 24 retrieves the shift positionsignal from shift position sensor 61 of the running informationretrieving section 26 via running information retrieving section 26.

In this embodiment, image switching function 241 of switching section 24determines whether either the top view image or the bird's eye viewimage should be displayed and switches the display contents.

If, at a step S631, switching section 24 receives the information to aneffect that the vehicle goes backward from the retrieved shift positionsignal from the retrieved shift position signal. In this case, switchingsection 24 selects the top view image at a step S631A. At a step S640,superposing section 23 superposes a vehicular graphic data p by means ofsuperposing section 23 if necessary. At a step S650, the top view imageafter the superposition process is displayed on display 4. The top viewimage processed at step S650 is shown in FIG. 6. In FIG. 6, f denotesthe forwarding direction of the vehicle. In this case, the directiontoward which the vehicle moves is a backward (rearward) direction. Inaddition, superposing section 23 may superpose arrow mark graphic data krepresenting the direction toward which the vehicle moves before thestop to clearly indicate the direction toward which the vehicle movesbefore the stop or may superpose a grid line g which provides the imagereference line net. An example of the top view image on which the arrowmark graphic data k representing the direction that the vehicle movesand grid line g are superposed is shown in FIG. 8.

As described above, the top view image is displayed during the backwardmotion of the vehicle when the vehicle is parked in a parking lot or ina garage. Hence, the driver can easily grasp the positional relationshipbetween a difference in the display form of the top view image and thebird's eye view image. Secondly, in a case where the vehicular runninginformation to the effect that the vehicle is running in the forwarddirection is received from the retrieved shift position signal at a stepS632, switching section 24 selects the bird's eye view image at a stepS632B. If necessary, at a step S640, superposing section 23 carries outthe superposition of the vehicular graphic data p′. Then, the bird's eyeview image is displayed after the superposition process on display 4 ata step S650. The bird's eye view image is shown in FIG. 7.

In FIG. 7, f denotes the direction (backward movement) that vehicle 10is moved. Furthermore, arrow mark graphic data k′ representing thedirection toward which vehicle 10 moves before stop may be superposed inorder to clearly indicate the movement direction before the stop. FIG. 9shows a display example of the bird's eye view image superposing arrowmark graphic data k′ and a grid line g′ (for the bird's eye viewpurpose) which is the reference line net of the display image. Asdescribed above, during the forward run in which there are many caseswhere the vehicle is driving while avoiding a collision of obstacles,the bird's eye view image is displayed so that the driver easily graspsthe sense of distance stereographically from the bird's eye view imageto the vehicle (vehicle 10 in which the image display apparatus in thisembodiment is mounted). Furthermore, vehicular graphic data p′, arrowmark graphic data k′, and gridline g′ are superposed. Thus, the bird'seye view image such that a stereographic sense of distance of theobstacle surrounding the vehicle and the vehicle surrounding are easilygrasped can be displayed to the vehicle driver through display 4.

If the running information to an effect that the vehicle is stopped isreceived from the shift position signal at a step S633, switchingsection 24 further receives the running information related to thehistory of the vehicle run or stop at a step S634. The runninginformation related to the history of the run or stop is received fromthe shift position signal related to the history of the vehicular run orstop. If the running information to an effect that the vehicle runs inthe reverse direction and, thereafter, has stopped at a step S635,switching section 24 selects the top view image at step S635A. Ifneeded, the superposition of vehicular graphic data p and arrow markgraphic data k representing the movement direction of the vehicle aresuperposed. The superposed top view image is displayed on display 4. Thetop view image displayed is the same as FIGS. 6 and 8.

On the other hand, if the running information to an effect that thevehicle has stopped after the vehicle runs in the forwarded (advanced)direction at a step S636 of FIG. 5, switching section 24 selects thebird's eye view image at a step S636B. If necessary, the superpositionof graphic data p and arrow mark graphic data k representing themovement direction of the vehicle are carried out. Display 4 serves todisplay the top view image on which the superposition process has beencarried out. The bird's eye view image displayed is the same as FIG. 7and FIG. 9.

In this way, the bird's eye view image is displayed in a case where thevehicle is stopped after the vehicle runs in the forward direction andthe top view image is displayed in a case where the vehicle is stoppedafter the vehicle runs in the backward direction. Thus, in a case wherethe vehicle frequently stops and runs in the forward direction or runsin the backward direction, whenever the vehicle stops, runs in theforward direction, and runs in the backward direction, a frequentswitching between the top view image and the bird's eye view image canbe prevented.

Referring back to step S610 of FIG. 5, an operation when the switchcommand is inputted to image display apparatus 100 will be describedbelow. Switching section 24 in the preferred embodiment performs theswitching of the display image in which a switch command by the driveris set to have a higher priority in a case where the switch command isinputted via manual switch 5. The modes of the switch commands are notspecifically limited. However, the switch command in this embodiment hasthree forms.

That is to say, the first switch command is a command to display the topview image when the vehicle runs in the backward direction, display thebird's eye view image when the vehicle runs in the backward direction,display the bird's eye view image when the vehicle runs in the forwarddirection, display either the top view image or bird's eye view imagedepending upon the direction toward which the vehicle moves before thevehicle has stopped, viz., display the top view image when the vehiclehas stopped after the vehicle runs in the backward direction and displaythe bird's eye view image when the vehicle has stopped after the vehicleruns in the forward direction. When the vehicle runs in the backwarddirection, there are many cases of such a situation that the drivermoves the vehicle to park or to enter a garage. In such a case asdescribed above, the top view image may be considered to make it easy tograsp a defined parking area and a relationship between the garage andthe vehicle. Hence, in a case where the driver inputs the first switchcommand via manual switch at a step S620, the same operations as stepsS630 and S650 are carried out. In addition, the second switch command isa command to display the bird's eye view image when the vehicle runs inthe forward direction, display the top view image when the vehicle runsin the backward direction, display either the top view image or thebird's eye view image depending upon the direction that the vehiclemoves before the vehicle has stopped when the vehicle has stopped, viz.,display the bird's eye view when the vehicle has stopped after thevehicle runs in the backward direction and display the top view imagewhen the vehicle has stopped after the vehicle runs in the backwarddirection and display the top view image when the vehicle has stoppedafter the vehicle runs in the forward direction. This second switchcommand prescribes a reverse image switching to the first switchcommand. Switching section 24 which has obtained the second switchingcommand receives the shift position signal from shift position sensor 61of running situation detecting section 6 via running informationreceiving section 26. If the running information to the effect that thevehicle runs in the backward direction at a step S671, switching section24 selects the bird's eye view image at a step S671B. If necessary,superposing section 23 superposes the graphic data on the bird's eyeview image at a step S680. The bird's eye view image after thesuperposition process is displayed on display 4 at a step S690 of FIG.5. The bird's eye view image display example is shown in FIG. 10. InFIG. 10, f denotes the direction toward which vehicle 10 runs (in thiscase, the vehicle runs in the backward direction). As shown in FIG. 10,the bird's eye view image is displayed during the backward run ofvehicle 10 so that the stereographic sense of distance between thevehicle and the obstacle can easily be grasped from the bird's eye viewimage. In a case where the vehicle receives the running information tothe effect that the vehicle is running in the forward direction from theobtained shift position signal at a step S672, switching section 24selects the top view image at a step S672A. If necessary, superposingsection 23 carries out the superposition of the vehicular graphic data pby means of superposing section 23. The superposed top view image isdisplayed on display 4 at a step S690. FIG. 11 shows a display exampleof the top view image in this case. In FIG. 11, f denotes the directiontoward which vehicle 10 moves (in this case, in the forward direction).In this way, the top view image is displayed during the forward run ofthe vehicle so that, in a case where the vehicle runs in the forwarddirection to park the vehicle in a predetermined area or to go into thegarage, the positional relationship between the predetermined parkingarea or garage and the vehicle can easily be grasped. Furthermore, in acase where the running information to the effect that the vehicle isstopped from the obtained shift position signal (at a step S673),switching section 24 receives the running information related to thehistory of the vehicular run or stop at a step S674. The runninginformation related to the history of the vehicular run or stop isobtained from the shift position signal related to the operation historyof the shift position signal related to the operation history of theshift position. In a case where the running information to the effectthat the vehicle runs in the backward direction and, thereafter, isstopped is received at a step S673, switching section 24 receives therunning information related to the history of the vehicular run or stopat a step S674 of FIG. 5. If the running information related to thevehicular run or stop is received from the shift position signal relatedto the operation history of the shift position (step S675 in FIG. 5),switching section 24 selects the bird's eye view at a step S675B. Ifnecessary, the superposition of the graphic data by means of superposingsection 23 is carried out. Display 4 displays the superposed bird's eyeview image. The displayed bird's eye view image is the same as FIG. 10.

On the other hand, if the running information to the effect that thevehicle stops after the vehicle runs in the forward direction at a stepS676, switching section 24 selects the top view image (at a step S676A).If necessary, the superposition of the graphic data by means ofsuperposing section 23. Display 4 displays the superposition processedtop view image. The top view image displayed is the same as FIG. 11. Inthis way, in a case where the vehicle stops after the vehicle runs inthe backward direction, the bird's eye view image is displayed. In acase where the vehicle runs in the forward or backward direction andstops and the vehicular run and stop are frequently repeated, a frequentswitching between the bird's eye view image and top view image can beprevented. The display is switched in accordance with the second switchcommand. Hence, even under a situation different from that normallypredicted, the display image in accordance with the running situationcan be displayed.

Next, if a hold command as a third switch command is inputted at a stepS660A, either the top view image or the bird's eye view image isdisplayed irrespective of the running situation (at a step S660B). Thehold command is a command to display the top view image, display thebird's eye view image, and continue to display either the top view imageor the bird's eye view image now presently displayed. Switching section24 switches the display of the top view image or the display of thebird's eye view image in accordance with the hold command. The holdcommand can display the image that the driver is desired to view evenunder a situation other than that presumed in the first or second switchcommand.

The switching operation of image display apparatus between the displayof the top view image and that of the bird's eye view image inaccordance with the running information related to the history of thevehicular run or stop has been described. In this embodiment, thedisplay of the top view image and that of the bird's eye view image canalso be carried out in accordance with the running information relatedto the running speed (vehicular velocity) of vehicle 10. The runninginformation related to the running speed (vehicular velocity) is derivedfrom vehicle velocity sensor 62 of running situation detecting section6. Switching section 24 receives the running information related to thevehicular velocity via running information receiving section 26.

An operation related to the switching of the display of the image inaccordance with the running information related to the vehicularvelocity will be described with reference to an operational flowchart ofFIG. 12. FIG. 12 shows a subroutine of the switch of the display at stepS6 shown in FIG. 4. It is noted that a basic operation is common to theoperation explained with reference to FIG. 5. Switching section 24, inthe alternative, switches the display image on the basis of the runninginformation received by running information receiving section 26 andswitches the image to be displayed on the basis of the vehicle driver'sswitch command accepted by command reception section 25. That is to say,if switching section 24 is activated to perform the switching of theimage to be displayed at a step S700 in FIG. 12, command reception(accepting) section 25 determines whether the switch command is inputtedfrom the vehicle driver via manual switch 5 at a step S710 shown in FIG.12. If the switch command from the driver is not inputted (No), theroutine goes to a step S730.

At step S730, switching section 24 receives a vehicular velocity signalfrom vehicular velocity sensor 62 of running situation detecting section6 via running information retrieving section 26. In this alternative,image switching function 241 of switching section 24 determines which ofthe top view image or the bird's eye view image should be displayed andswitches the image display.

First, at a step S731, if the vehicular running information to theeffect that running velocity Y of the vehicle is lower than 10 Km/h fromthe received running velocity signal, switching section 24 selects thetop view image at a step S731A in FIG. 12. If needed, the superpositionof vehicular graphic data p by means of superposing section 23 iscarried out (a step S740 shown in FIG. 12). Then, the top view imageafter the superposition process is displayed on display 4 at a step S750shown in FIG. 12. This top view image display example is shown in FIGS.6 and 8. In this way, in a case where the running velocity is low insuch a case where the vehicle goes into the predetermined parking area,the top view image is displayed under the situation under which therunning velocity is low. The vehicle driver can easily grasp thepositional relationship between the vehicle and parking area from thedisplay of the top view image.

Secondly, in a case where the running velocity of the vehicle is equalto or higher than 10 Km/h from the received running velocity signal at astep S732, switching section 24 selects the bird's eye view image at astep S732B in FIG. 12. If necessary, the superposition of the vehiculargraphic data p′ by means of superposing section 23 is carried out atstep S740. The bird's eye view image after the superposition process isended is displayed on display 4 at step S750. The display examples ofthe bird's eye view images in this situation are shown in FIGS. 7 and 9.As described above, the bird's eye view image is displayed under such asituation that the vehicle is running at a speed which is not the lowspeed. The driver can, thus, recognize not only the vehicle surroundingbut also a far away from the forward direction of the vehicle orrearward direction of the vehicle.

Referring back to step S610 of FIG. 4, an operation in a case where oneof three switch commands is inputted will be described below. The switchcommands have three forms in this alternative.

First, the first switch command is a command to display the top viewimage when the vehicle runs at a speed lower than 10 Km/h and to displaythe bird's eye view image when the vehicle runs at a speed equal to orhigher than 10 Km/h. If the vehicle is running at the low speed, thereare many cases where the vehicle is parked or the vehicle goes into thegarage. The second switch command prescribes the image switching whichis reverse to the first switch command. Even if the vehicle is runningat a low speed, there is often the case where the bird's eye view imagewhich is easy to grasp the stereographical sense of distance between thevehicle and the obstacle. Even in a case where a vehicular relativepositional relationship is easier to be grasped even when the vehicle isrunning at a speed not at a low speed, there is often the case where thetop view image which is easy to grasp a relative positional relationshipof the vehicle.

In a case where the vehicle runs at a low speed, there are many caseswhere the vehicle driver parks the vehicle and moves the vehicle toenter into the garage. In this situation, viewing the top view image isconsidered to be easier to grasp the positional relationship between thedefined parking area (or garage space) and the vehicle. In a case wherethe vehicle runs at a speed higher than the low speed, viewing thebird's eye view image which can look out over a wide range of thesurrounding of the vehicle is easier to confirm the direction towardwhich the vehicle moves. An operation in response to the first switchcommand has the same contents as the basic operation. Hence, if thefirst switch command is inputted by the vehicle driver at step S720, thesame series of operations from step S730 to step S750 are carried out.

Next, the second switch command is the command to display the bird's eyeview image when the vehicle runs at a speed lower than 10 Km/h and todisplay the top view image when the vehicle runs at a speed equal to orhigher than 10 Km/h. The second switch command prescribes the displayimage switching reverse to that in the case of the first switch command.This is because even if the vehicle runs at a low speed, there is oftena case where the bird's eye view image is to be displayed which is easyto grasp the stereographic sense of distance between the vehicle and theobstacle and there is often the case even if the vehicle runs at a speednot at the low speed, the top view image which is easier to grasp therelative positional relationship is to be displayed.

Furthermore, command reception (accepting) section 25 receives the holdcommand as the third switch command signal. The hold command displayswhich of either the top view image or the bird's eye view image isdisplayed. If the first switch command is selectively inputted by thedriver at step S720, the routine goes to step S730. The above-describedoperation is carried out in the same way as described before. If thesecond switch command is inputted (Yes at step S760), the routine goesto a step S770 shown in FIG. 12. Switching section 24 receiving thesecond switch command receiving the running velocity signal fromvehicular velocity sensor 62 of running situation detecting section 6via running information receiving section 26. The vehicular runninginformation to the effect that the running speed Y of the vehicle islower than 10 Km/h from the received running speed signal at a step S771of FIG. 12, switching section 24 selects the bird's eye view image at astep S771B. If necessary, the superposition of the graphic data by meansof superposing section 23 is carried out by superposing section 23 at astep S780. The bird's eye view image after the superposition process isdisplayed on display 4 (a step S790). On the other hand, if the runninginformation to the effect that running speed Y of the vehicle is equalto or higher than 10 Km/h from the received running speed signal at astep S772, switching section 24 selects the top view image at a stepS772A. If necessary, superposing section 23 superposes the top viewimage on the graphic data at a step S780. The top view image after thesuperposition process is displayed on display 4 at a step S790 of FIG.12. The display image is switched in accordance with the second switchcommand. Thus, even under a situation different from that which wouldnormally be predicted, the image can be displayed which accords with therunning situation.

Next, if the hold command is inputted as the third switch command (astep S761), either the top view image or the bird's eye view image isdisplayed irrespective of the running situation. The hold command is thecommand to display the top view image, to display the bird's eye viewimage, or to continue to display either of the top view image or thebird's eye view image which is now currently displayed. Switchingsection 24 switches the display image of either the top view image orbird's eye view image in accordance with the hold command. This holdcommand can serve to display the image that the vehicle driver desiresto view even under a situation other than that would presume in thefirst or second switch command. The hold command is described at stepsS761 and S762 in FIG. 12.

The image display apparatus in the first embodiment has the followingadvantages. That is to say, the display image is switched between thetop view image and the bird's eye view image in accordance with therunning information related to the running situation so that anappropriate image in accordance with the driver's driving operation canbe displayed and the drive operation by the vehicle driver can beassisted.

In details, in a case where the switch of the display image is carriedout in accordance with the running situation related to the directiontoward which the vehicle runs (moves), during the vehicular run in thebackward direction, for example, in a case where the vehicle drivermoves the vehicle to enter into the predetermined parking area or thegarage while running the vehicle in the backward direction, the top viewimage approximately vertically looking down to the vehicle from theupper sky above the vehicle is displayed so that the vehicle driver caneasily grasp the relationship between the vehicle and parking area. Onthe other hand, during the vehicular forwarding directional movement,for example, in a case where the vehicle runs in the forward directionwhile avoiding the collision against the obstacle located at thesurrounding of the vehicle, the bird's eye view image is displayedlooking down to the vehicle with the predetermined looking down anglefrom the upper sky above the vehicle. The driver can easily grasp thestereographic sense of distance of the obstacle located at thesurrounding of the vehicle from the bird's eye view image.

In addition, in a case where the display switch of the display inaccordance with the running information related to the running speed ofthe vehicle is carried out, the vehicle runs at the low speed (forexample, lower than 10 Km/h). At this time, suppose that the vehicledriver moves the vehicle to enter into the predetermined parking area orthe garage. In this case, the top view image approximately verticallylooking down to the vehicle from the upper sky above the vehicle isdisplayed so that the vehicle driver can easily move the vehicle toenter into the predetermined parking area or the garage while confirmingthe relationship between the vehicle (vehicle body) and the parking areathrough the top view image. On the other hand, in a case where thevehicle runs at a speed equal to or higher than the low speed (forexample, 10 Km/h or higher), the bird's eye view described above is, inturn, displayed so that the driver can drive the vehicle whileconfirming the wide range of the forwarding direction including thevehicle and the surrounding of the vehicle through the bird's eye viewimage. Furthermore, when the switch command is inputted by the vehicledriver, the display of the image is switched in accordance with theaccepted switch command. Thus, even under such a situation that thevehicle driver moves the vehicle to enter into the parking area orgarage and moves the vehicle to run in the backward direction by a longdistance, an appropriate image can be displayed for a driving assistanceof the vehicle driver.

Vehicular graphical data p or p′ are superposed on either the top viewimage or bird's eye view image so that a portion of the photographeddata which cannot be obtained as the photograph image due to the deadangle for cameras 1 can be compensated by stereographic vehiculargraphic data p or p′. Furthermore, since the stereographic vehiculargraphic data p or p′ representing the vehicle stereographically issuperposed, an actual vehicular shape including the stereographic senseof distance in the display image can be expressed. That is to say, thesense of distance in a direction of height of the vehicle can beexpressed. Images of a surrounding of tire wheels of the vehicle, of thesurrounding of rear bumpers, of the surrounding of front bumpers, and ofthe surrounding of sill outers which are easy to be the dead angles forcameras 1 can also be compensated by the vehicular graphic data p or p′.

In addition, since arrow mark graphic data k or k′ indicating thedirection toward which the vehicle moves is superposed on the top viewimage or the bird's eye view image, the direction that the vehicle ismoving can easily be recognized from the image displayed. Since gridline g or g′ indicating the reference line net of the image issuperposed on the top view image or the bird's eye view image, thedifference in the display form between the top view image and the bird'seye view image can easily be recognized.

Second Embodiment

The image display apparatus in a second preferred embodiment accordingto the present invention will be described below. In the secondembodiment, only a technique of switching the display image in switchingsection 24 is different from the first embodiment and the fundamentaloperation is generally the same as described in the first embodiment.Herein, a duplicate explanation from the first embodiment is avoided andonly a difference point from the first embodiment will be describedbelow.

When image switching function 241 of switching section 24 is activatedin the first embodiment, image switching section 241 determines the formof the display image displayed in accordance with the running situationof the vehicle, the transforming process of transforming section 22 iscontrolled to switch the display image. On the other hand, in the secondembodiment, viewing point switching function 242 of switching section 24shown in FIG. 1 is activated. Viewing point switching function 242 makespreviously the position of the viewing point accord with the vehicularrunning situation corresponding to the looking down angle in accordancewith the running information. This correspondent relationship may makethe running information correspondent to the position of the viewingpoint and/or looking down angle. This corresponding relationship maymake the running information, the position of the viewing point, and/orlooking down angle correspond to each other according to a table onwhich the running information, the position of the viewing point, andlooking down angle are arranged. Or alternatively, these correspondencerelationship may be in accordance with an equation to derive theposition of the viewing point and/or looking down angle from the runninginformation. Viewing point switching function 242 refers to thecorresponding running information, the position of the viewing point,and looking down angle to set the viewing point of the display imagetransformed by transforming section 22 and the looking down angle. Theviewing point and looking down angle of the display image transformed bytransforming section 22 are set by viewing point switching function 242.The position of the viewing point and looking down angle in accordancewith the running information are calculated. When these parameters areset, the switch command is supplied to transformation section 22together with signals indicating the position of the viewing point andthe looking down angle. Transforming section 22 transforms the top viewimage synthesized by means of the synthesizing section 21 in accordancewith a transformation command into an image looking down to the vehiclefrom the predetermined viewing point through the predetermined lookingdown angle.

FIG. 13 shows an operational flowchart for explaining viewing pointswitching function 242 of switching section 24 in the second embodimentof the image display apparatus according to the present invention. Thisoperation shown in FIG. 13 is a subroutine of step S6 shown in FIG. 4 atwhich the switching of the display image is carried out.

At a step S16 in FIG. 13, the routine of FIG. 4 enters this subroutine.At a step S17, viewing point switching function 242 is activated.Viewing point switching function 242 switches and sets the position ofthe viewing point and looking down angle in accordance with the runninginformation. A transformation command including the information on theposition of the switched (or set) viewing point and looking down anglethereof is supplied from viewing point switching function 242 totransforming section 22 at a step S18 of FIG. 13. If the position of theviewing point of the displayed image and looking down angle thereof arethe same as the position of the viewing point of the top view image andthe looking down angle synthesized by synthesizing section 21 (Yes at astep S19), the top view image is directly supplied to superposingsection 23 to carry out the superposition process of the graphic data ata step S23 in FIG. 13 and the top view image is finally displayedthrough display 4 at a step S24 in FIG. 13. On the other hand, if thedisplay image is an image different from the top view image before thetransformation, namely, if the position of the viewing point of thedisplayed image and the looking down angle thereof are different fromthose of the top view image (No at step S19), transforming section 22reads the coordinate transformation equation 33 in accordance with theposition of the viewing point and the looking down angle included in theswitch command from storing section 30 at a step S20 and transforms thetop view image synthesized by means of synthesizing section 21 into thebird's eye view image which is an image looking down to the vehicle fromthe viewing point set on the basis of the transformation equation 33read through the set looking down angle at a step S22. The graphic datais superposed on the bird's eye view image to be displayed on display 4at steps S23 and S25.

As described above, the image display apparatus in the second embodimenthas the following advantage in addition to the advantages that the firstembodiment has. That is to say, since the position of the viewing pointof the display image and looking down angle thereof can arbitrarily beswitched in accordance with the running information indicating therunning situation of the vehicle, an optimum image can be displayed whenassisting the drive of the vehicle by the vehicle driver during thevarious running situations.

In each of the first and second embodiments, the image display apparatusfor the automotive vehicle has been described. However, each of thefirst and second embodiment is applicable to a case wherein a vehicularimage display method is applied or the computer which is operated inaccordance with an image display program of the vehicle. The sameadvantages as described above can also be achieved in theabove-described case.

Third Embodiment

FIG. 14 shows an arrangement of the image display apparatus in a thirdpreferred embodiment according to the present invention. A plurality ofcameras 1 a, 1 b, 1 c, 1 d, - - - are displayed on high positions of avehicular body outer peripheral portion at appropriate spatial intervalsto one another to photograph the vehicle surrounding. FIG. 15 shows anexample of arrangement portions of cameras 1 a through 1 h. It is notedthat although, in this embodiment, a photograph view angle of eachcamera 1 a, 1 b, - - - , 1 h is mutually overlapped and eight cameras 1a through 1 h are arranged on the vehicular (vehicle body) outer edgeportion, the number of cameras and arrangement thereof to photograph thevehicular surrounding are not limited to this example of FIG. 15. Inaddition, the cameras 1 a through 1 h are arranged over the wholeperiphery of the vehicle to photograph the surrounding of the vehicle asshown in FIG. 15. However, the present invention is applicable to thevehicular image display apparatus in which a single camera or aplurality of cameras by which part or parts of the whole surrounding ofthe vehicle such as a vehicular rearward portion or a vehicular lateralside portion are photographed. Photographing condition detectingapparatus 2A detects photograph conditions of cameras 1 a through 1 hsuch as mounting locations of the cameras, directions of optical axes ofphotograph lens thereof, and characteristics of the photograph lensthereof. An image processing section 3 includes a microcomputer having amemory, an A/D converter and other peripheral parts, synthesizes theimages of the vehicle and the surrounding of the vehicle photographed bymeans of the plurality of cameras 1 a, 1 b, 1 c, 1 d, - - - , andcommands display 4 to display the vehicular surrounding image viewedfrom the upper portion of the vehicle with no image distortion. Imageprocessing section 3, in terms of software of the microcomputer,includes: a tire wheel detecting section 3 a which detects and performsthe image processing for the image of the surrounding of the vehicle todetect a tire wheel of another vehicle included in the image. Pseudovehicular image drawing section 3 b draws a pseudo image (hereinafter,referred to as a pseudo vehicular image) viewed from an upper portion ofthe vehicle in accordance with a position of the tire wheel of the othervehicle detected by tire wheel detecting section 3 a. Surrounding imagesynthesizing section 3 c performs a perspective view transformation fromthe vehicular surrounding images photographed by the plurality ofcameras 1 a, 1 b, 1 c, 1 d, - - - respectively into the vehicularsurrounding image viewed from the viewing point above the vehicle tosynthesize these vehicular surrounding images into one sheet ofvehicular surrounding image. Image synthesizing section 3 d synthesizesthe vehicular surrounding image synthesized by surrounding imagesynthesizing section 3 c into one sheet with the pseudo vehicular imagedrawn by pseudo vehicular image drawing section 3 b to generate theimage surrounding the vehicle.

Next, an operation of the third embodiment of the image displayapparatus described above will be described by referring to an exampleof parking the vehicle at a parking lot. FIG. 16 shows an operationalflowchart representing a vehicular surrounding image display programexecuted by the microcomputer constituting image processing section 3.

Image processing section 3 executes the program shown in FIG. 16repeatedly whenever a power supply for image processing section 3 isturned on. At a step S1′, the surrounding of the vehicle is photographedby means of cameras 1 a, 1 b, - - - , 1 h arranged on the vehicle bodyouter edge portion as shown in FIG. 15. At the next step S2′,surrounding image synthesizing section 3 c carries out the perspectivetransformation from the image of the surrounding of the vehiclephotographed by each camera 1 a, 1 b, - - - , 1 h to an image viewedfrom the upper position of the vehicle body on the basis of thephotograph conditions such as the mounting locations of the respectivecameras 1 a, 1 b, - - - , the directions of the optical axes of thephotograph lens of cameras 1 a, 1 b, - - - , and characteristics ofphotograph lens thereof detected by photographing condition detectingapparatus 2A. FIG. 17 shows a display example of an image photographedby means of one 1 f of cameras 1 a, 1 b, - - - , 1 h which is located ona rear right side of vehicle 500. As shown in FIG. 17, another vehicle 6is parked at the rear right side of vehicle 500 (10). FIG. 18 shows adisplay example of the perspective view image generated from theplurality of vehicular surrounding images photographed by the pluralityof cameras 1 a, 1 b, - - - , 1 h with the upper portion of the vehicleas the viewing point and synthesized with a pseudo image 5 a of vehicle500 as a center. In FIG. 18, the image of the other vehicle 6 parked atthe backward direction of the right rear side of the vehicle 500 is theimage photographed by one if of the cameras 1 a through 1 h located atthe rear right side of the vehicle body perspectively transformed andsynthesized into the image viewed from the upper portion of vehicle 500.In FIG. 18, if the image of camera 1 f mounted at the portion of thevehicle body near to a roof of the vehicle is transformed into the imageviewed from the viewing point having a height near to an infinite point,it is not transformed into the image correctly straightly upper part ofthe vehicle and the image is distorted. It is noted that since thevehicle 500 itself (also called, a host vehicle in which the imagedisplay apparatus according to the present invention is mounted) is notphotographed by the plurality of cameras 1 a, 1 b, - - - , 1 h, pseudoimage 5 a of vehicle itself 500 is previously prepared and synthesizedwith the image of the surrounding of the vehicle. In this embodiment,the surrounding image of the vehicle without distortion viewed from theupper portion of the vehicle is generated as described below.

A tire (a tire portion of the tire wheel) is usually black in color andis of a characteristic shape such as a circle or ellipse in thephotographed image of cameras 1 a, 1 b, - - - , 1 h. Hence, byextracting a black portion whose shape is the circle or ellipse from theimage of the surrounding of the vehicle, the tire can easily beidentified. In addition, since the tire wheel within the image of thesurrounding of the vehicle is viewed whose shape becomes differentaccording to the viewing position, the position between host vehicle 500(itself) and the other vehicle 6 can be recognized according to theshape of the tire wheel. That is to say, with tire wheel detectingpatterns in accordance with the positions of the vehicular surroundingimage previously generated and stored, a pattern matching on the imagesof the tire wheel detecting patterns and the surrounding of vehicle 500is carried out on the vehicular surrounding image. On the basis of oneof the wheel detecting patterns and the tire wheel position shapepattern which is coincident with each other, a positional relationshipbetween the vehicle itself (500) and the other vehicle (6) can berecognized.

Referring back to a step S3′ in FIG. 16, tire wheel detecting section 3a divides the vehicular surrounding image to be under a pattern matchinginto a black color system and no black color system. With the blackcolor system kept unchanged and a system other than the black colorsystem is changed to a white, the vehicular surrounding the image istransformed into a monochromatic (black-and-white) image. It is notedthat, even if it is a black color, the black which can be identified asa metal color is set to a white color. Then, an edge of themonochromatic image after the transformation is emphasized by a certainlightness (edge emphasis) and this emphasized processed image isgenerated. FIG. 19 shows the display example of the monochromatic edgeemphasis processed image.

As described above, since the shape of the tire of the other vehicle 6is viewed to be varied depending upon a position thereof on thevehicular surrounding image shown in FIG. 19, the pattern matching usingthe tire wheel detecting patterns for each position on the vehicularsurrounding image is carried out so that the tire wheel position of theother vehicle 6 with reference to the position of the vehicle itself 500is detected. At a step S4′ in FIG. 16, pseudo vehicular image drawingsection 3 b draws the pseudo vehicular image which matches with the tirewheel position of the other vehicle 6.

At a step S5′ in FIG. 16, image synthesizing section 3 d overwrites thepseudo vehicular image drawn by pseudo vehicular image drawing section 3b on the tire wheel position detected by tire wheel detecting section 3a on the image of the surrounding of the vehicle and is synthesized togenerate a final vehicular surrounding image as shown in FIG. 20. InFIG. 20, 6 a denotes the pseudo vehicular image drawn by pseudovehicular image drawing section 3 b as the other vehicle. If this pseudovehicular image 6 a shown in FIG. 20 is compared with the image of theother vehicle 6 shown in FIG. 18, the image of the other vehicle 6 shownin FIG. 18 is a distorted image as if it were viewed from an obliqueupper portion of the other vehicle. Whereas, pseudo vehicular image 6 ashown in FIG. 20 is the image viewed from the upper portion of thevehicle correctly. At the next step S6′, image processing unit 3displays the image of the synthesized vehicular surrounding image ofvehicle itself 500 through display 4.

As described above, in the third embodiment, the tire wheel of othervehicle 6 is detected from the contents of the vehicular surroundingimage perspectively transformed and synthesized from the viewing pointabove the vehicle photographed by cameras 1 a, 1 b, - - - , pseudovehicular image 6 a of the other vehicle 6 which matches with the tirewheel position of other vehicle 6 is drawn, and the pseudo vehicularimage 6 a is overwritten and displayed on the vehicular surroundingimage. Therefore, the vehicular surrounding image without the imagedistortion of the vehicular surrounding image viewed correctly from theupper portion of the host vehicle can be displayed. Consequently,erroneous recognition of the distance and direction to the other vehicledue to the distortion of the vehicular surrounding image and unpleasantfeeling given to the vehicular occupant can be avoided.

Fourth Embodiment

In the third embodiment, the integrated image photographed by theplurality of cameras located at the outer periphery of the vehicle bodyis perspectively transformed into the vehicular surrounding image viewedfrom the upper position of the vehicle and, thereafter, the patternmatching is carried out using tire wheel detecting patterns to detectthe position of the tire wheel of the other vehicle. In the thirdembodiment of the detecting method of the tire wheel position of theother vehicle, the tire wheel detecting patterns which are distorted areneeded to be prepared in accordance with the positions of the tirewheels on the vehicular surrounding image. On the other hand, in thefourth embodiment, the above-described pattern matching is carried outon the image photographed by the cameras before the perspectivetransformation to the image viewed from the upper portion above thevehicle. The shape (or contour) of the tire wheel of the vehicle viewedfrom each image photographed by the cameras is generally circular orelliptical and photographed tire wheel vertical expansion/shrinkage rateand photographed tire wheel size are related to a photograph distance,viz., the distance from the tire wheel to the vehicle (itself) 500.Hence, the vertical expansion (shrinkage) rate and size of the tirewheel shape are varied in accordance with the position on thephotographed image by each camera. In addition, a horizontal (left andright) expansion/shrinkage rate of the tire wheel shape is varied inaccordance with a gradient of the vehicle with respect to a verticaldirection on the image. Therefore, in the fourth embodiment, a pluralityof tire wheel detecting patterns whose vertical expansion/shrinkage rateand the size of the tire wheel are varied in accordance with verticalpositions of the tire wheels on the image photographed by each camera 1(1 a, 1 b, - - - , 1 h). The pattern matching is carried out in such away that one of the tire wheel detecting patterns which corresponds tothe tire wheel position on the image photographed by each camera isselected while the horizontal expansion/shrinkage rate of each tirewheel detecting pattern is varied in accordance with the gradient of thevehicle. In the fourth embodiment, using such tire wheel detectingpatterns described above, the pattern matching is carried out on theimage photographed by the camera, as shown in FIG. 22, to detect thetire wheel position of the other vehicle.

It is noted that, in an example shown in FIG. 22, the image photographedby the camera to be subjected to the pattern matching is divided intothe black color system and the system other than the black color system,with the black system left unchanged (black) and with no black colorsystem changed to the white color so that the monochromatic image(black-and-white) is converted. An image on which an edge of themonochrome image is emphasized to a certain lightness difference isgenerated. On the image, the tire wheel position of the other vehicle isdetected using each tire wheel detecting pattern adopted in the fourthembodiment.

In the fourth embodiment, the tire wheel detecting pattern in accordancewith each position on the photographed image by each camera is used inaccordance with the detected tire wheel position and the patternmatching is carried out while varying the horizontal expansion/shrinkagerate of the wheel detecting pattern in accordance with the gradient ofthe vehicle. Hence, as compared with the third preferred embodiment inwhich the pattern matching is carried out on the vehicular surroundingimage after the perspective transformation for the image photographed byeach camera and viewed from the upper end of the vehicle, the positionof the tire wheel of the other vehicle can accurately be detected. Theoperation other than the detecting method of the tire wheel position isthe same as described in the third embodiment and its explanation willherein be omitted. In each of the third and fourth embodiments, the tirewheel shape on the image on which the pattern matching is carried out,as shown in FIG. 19, is of a circle or an ellipse. Hence, as shown inFIG. 23, as the edge is being detected in a radial direction from adetection point on the image, two concentric edges are detected. Whenthese edge shapes satisfy the condition of the tire wheel, these shapedimages are deemed to be the tire wheel. In addition, a wheel base ofanother vehicle can be recognized according to the tire wheel positionof the other vehicle detected by tire wheel detecting section 3 a,pseudo vehicular image drawing section 3 b draws the pseudo vehicularimage which matches with the wheel base of the other vehicle andoverwrites the pseudo vehicular image on the vehicular surrounding imageby means of image synthesizing section 3 d shown in FIG. 14 so that theimage of the other vehicle which is approximate to an actual dimensionand shape can be displayed. It is noted that, in each of the third andfourth embodiments, there is a possibility that an actual distortedvehicle is larger than the pseudo vehicular image and the vehicle isoverflowed (or projected) from the pseudo vehicular image. Thus, at thistime, such a pseudo vehicular image that its whole length (vehicularlongitudinal length) is longer than an average whole length which wouldbe considered from the wheel base of the other vehicle is drawn so thatthe image of the other vehicle which is actually distorted can beprevented from being overflowed (or projected) and displayed from thepseudo vehicular image. It is noted that, even if such a projection asdescribed above is present to some degree, the whole length of the othervehicle parked at a lateral side of the vehicle does not disturb aparking operation of the vehicle itself (host vehicle). Hence, noproblem arises.

In addition, for another vehicle which is parked at either a front areaor a rear area of the vehicle itself (so-called, the host vehicle), eachbody color of this other vehicle and the pseudo vehicular image is setto be the same. Hence, even if the image of the actually distorted othervehicle is overflowed (projected) from the pseudo vehicular image anddisplayed, no un-match (difference or unpleasant) feeling is given to avehicular occupant.

Cameras 1 a, 1 b, 1 c, 1 d, - - - constitute photographing means, imageprocessing section 3 constitute perspective view transforming means,another vehicle detecting means, pseudo vehicular image drawing means,and image synthesizing means. Display 4 constitutes display means. It isnoted that although, in the whole specification, the term ofsuperposition is used, the term of the superposition has the samemeaning as a term of superimpose.

Various changes and modifications may be made without departing from thesprit and scope of the present invention which is to be defined in theappended claims.

The entire contents of two Japanese Patent Applications No. 2002-151143(filed in Japan on May 24, 2002) and No. 2002-116039 (filed in Japan onApr. 18, 2002) are herein incorporated by reference. The scope of theinvention is defined with reference to the following claims.

1. An image display apparatus for an automotive vehicle, comprising: aphotographing section that photographs a field near the vehicle, thephotographing section including a plurality of cameras disposed tophotograph respective fields near the vehicle; a display imagegenerating section that includes an image synthesizing sectionconfigured to synthesize video images photographed by the plurality ofcameras and that generates a top view display image looking down a wholepart of the vehicle through an approximately vertical angle from a firstviewing point on an upper sky of the vehicle and bird's eye view displayimages looking down the whole part of the vehicle through apredetermined looking-down angle from a second viewing point at whichthe first viewing point is moved toward a front portion of a vehicularrunning direction and from a third viewing point at which the firstviewing point is moved toward a backward portion of the vehicularrunning direction; a display section configured to display one of theimages generated by the display image generating section; a displayimage switching section that switches the displayed image to another oneof the generated display images; and a running information receivingsection that receives running information of the vehicle, the displayimage switching section switches the displayed image in accordance withthe received information of the vehicle; wherein: the runninginformation receiving section is configured to receive the runninginformation related to a detected direction toward which the vehiclemoves; and the display image switching section is configured to switchthe displayed image from a bird's eye view image when the vehicle isrunning in a forward direction, to a top view image when the vehicle isrunning in a backward direction.
 2. An image display apparatus for anautomotive vehicle as claimed in claim 1, wherein: the image displayapparatus further comprises a running information receiving section thatreceives running information of the vehicle; the display images includea top view image and a bird's eye view image, the running informationreceiving section receives the running information related to a historyof vehicle movements, and the display image switching section switchesthe displayed image from a bird's eye view image when the vehicle stopsafter moving in a forward direction to a top view image when the vehiclestops after moving in a backward direction.
 3. An image displayapparatus for an automotive vehicle as claimed in claim 1, wherein: theimages generated by the display image generating section include a topview image and a bird's eye view image, the running informationreceiving section receives the running information related to a velocityof the vehicle, the display image switching section switches thedisplayed image to a bird's eye view image when the vehicle is runningat a speed no less than a predetermined value, and switches the displayimage to display a top view image when the vehicle is running at a speedlower than the predetermined value.
 4. An image display apparatus for anautomotive vehicle as claimed in claim 1, wherein the runninginformation receiving section receives the running information relatedto a vehicular running status from a shift position sensor to detect ashift position of the vehicle or a vehicular velocity sensor to detect avehicular running velocity.
 5. An image display apparatus for anautomotive vehicle as claimed in claim 1, wherein: the display imagegenerating section further comprises a command reception section thatreceives an external switch command, and the display image switchingsection switches the display image displayed through the display sectionto one of a top view image and a bird's eye view image based on theexternal switch command.
 6. An image display apparatus for an automotivevehicle as claimed in claim 5, wherein the display image switchingsection switches the display image displayed through the display sectionto one of the top view image and the bird's eye view image in accordancewith the switch command received by the command reception section andthe running information received by the running information receivingsection.
 7. An image display apparatus for an automotive vehicle asclaimed in claim 6, wherein: the command reception section receives oneof first, second, and third commands, the first command is a command todisplay the bird's eye view image through the display section when thevehicle is running in a forward direction and to display the top viewimage through the display section when the vehicle is running in abackward direction, the second command is a command to display the topview image through the display section when the vehicle is running inthe forward direction and to display the bird's eye view image throughthe display section when the vehicle is running in the backwarddirection, and the third command is a command to display one of the topview image and the bird's eye view image through the display sectionirrespective of a vehicular running status.
 8. An image displayapparatus for an automotive vehicle as claimed in claim 1 furthercomprising a superposing section that superposes at least one ofvehicular graphic data projected from a respective viewing point towardthe vehicle, arrow mark graphic data indicating a direction toward whichthe vehicle moves, and a grid line indicating a reference line.
 9. Animage display apparatus for an automotive vehicle, comprising: aphotographing section that photographs a field near the vehicle; adisplay image generating section that generates a plurality of displayimages based on photographed data supplied from the photographingsection, each of the plurality of display images having a differentviewing point and a looking down angle; a display section configured todisplay one of the display images generated by the display imagegenerating section; a display image switching section that switches thedisplayed image to another one of the display images; a surroundingvehicle detecting section that detects a surrounding vehicle near thevehicle based on the photographed data; and a pseudo vehicular imagedrawing section configured to draw a pseudo vehicular image, wherein atleast one of the display images is synthesized with the pseudo vehicularimage, wherein: the display image generating section comprises aperspective view transforming section that transforms a respectivedisplay image into a perspective view image, and the surrounding vehicledetecting section detects a wheel of another vehicle based on at leastone of a vehicular surrounding image generated by the perspective viewtransforming section and a vehicular surrounding image photographed bythe photographing section to detect a position of the other vehicle. 10.An image display apparatus for an automotive vehicle as claimed in claim9, wherein the pseudo vehicular image drawing section estimates a wheelbase of the other vehicle based on a position of the wheel detected bythe surrounding vehicle detecting section and draws the pseudo vehicularimage matching the estimated wheel base.
 11. An image display apparatusfor an automotive vehicle as claimed in claim 10, wherein the pseudovehicular image drawing section draws the pseudo vehicular image havinga longitudinal length longer than that of the other vehiclecorresponding to the estimated wheel base.
 12. An image displayapparatus for an automotive vehicle as claimed in claim 9, wherein thepseudo vehicular image drawing section draws the pseudo vehicular imagehaving the same body color as another vehicle which is located at afront or rear area of the vehicle.
 13. An image display apparatus for anautomotive vehicle, comprising: photographing means for photographing afield near the vehicle, the photographing section including a pluralityof cameras disposed to photograph respective fields near the vehicle;display image generating means including an image synthesizing sectionconfigured to synthesize video images photographed by the plurality ofcameras, for generating a top view display image looking down a wholepart of the vehicle through an approximately vertical angle from a firstviewing point on an upper sky of the vehicle and bird's eye view displayimages looking down the whole part of the vehicle through apredetermined looking-down angle from a second viewing point at whichthe first viewing point is moved toward a front portion of a vehicularrunning direction and from a third viewing point at which the firstviewing point is moved toward a backward portion of the vehicularrunning direction; display means through which one of the display imagesgenerated by the display image generating means is displayed; displayimage switching means for switching the displayed image generated by thedisplay image generating means and displayed through the display meansto another one of the display images; and a running informationreceiving section that receives running information of the vehicle, thedisplay image switching section switches the displayed image inaccordance with the received information of the vehicle; wherein: therunning information receiving section is configured to receive therunning information related to a detected direction toward which thevehicle moves; and the display image switching section is configured toswitch the displayed image from a bird's eye view image when the vehicleis running in a forward direction, to a top view image when the vehicleis running in a backward direction.
 14. An image display method for anautomotive vehicle, comprising: generating images of respective fieldsnear the vehicle by using a plurality of cameras disposed to photographthe respective fields near the vehicle; synthesizing the video images;receiving running information related to a running status of thevehicle; generating a top view display image looking down a whole partof the vehicle through an approximately vertical angle from a firstviewing point on an upper sky of the vehicle and bird's eye view displayimages looking down the whole part of the vehicle through apredetermined looking-down angle from a second viewing point at whichthe first viewing point is moved toward a front portion of a vehicularrunning direction and from a third viewing point at which the firstviewing point is moved toward a backward portion of the vehicularrunning direction; and switching the displayed image to another one ofthe generated display images in accordance with the running information;wherein: the running information relates to a detected direction towardwhich the vehicle moves; and the displayed image is switched from abird's eye view image when the vehicle is running in a forwarddirection, to a top view image when the vehicle is running in a backwarddirection.
 15. An image display method for an automotive vehicle,comprising: generating images of respective fields near the vehicleusing a plurality of cameras disposed to photograph the respectivefields near the vehicle; synthesizing the video images; generating a topview display image looking down a whole part of the vehicle through anapproximately vertical angle from a first viewing point on an upper skyof the vehicle and bird's eye view display images looking down the wholepart of the vehicle through a predetermined looking-down angle from asecond viewing point at which the first viewing point is moved toward afront portion of a vehicular running direction and from a third viewingpoint at which the first viewing point is moved toward a backwardportion of the vehicular running direction; displaying one of thegenerated images; switching the displayed image to another one of thegenerated images, wherein the displayed image is switched from a bird'seye view image when the vehicle is running in a forward direction, to atop view image when the vehicle is running in a backward direction;detecting a surrounding vehicle near the vehicle from the photographeddata; drawing a pseudo vehicular image; and synthesizing the pseudovehicle image with one of the images.
 16. An image display program for acomputer of an automotive vehicle, when executed by the computer,controlling the computer to: receive images of respective fields nearthe vehicle obtained by a plurality of cameras disposed to photographthe respective fields near the vehicle; synthesize images obtained bythe plurality of cameras; receive running information related to avehicular running status, wherein the running information relates to adetected direction toward which the vehicle moves; generate a top viewdisplay image looking down a whole part of the vehicle through anapproximately vertical angle from a first viewing point on an upper skyof the vehicle and bird's eye view display images looking down the wholepart of the vehicle through a predetermined looking-down angle from asecond viewing point at which the first viewing point is moved toward afront portion of a vehicular running direction and from a third viewingpoint at which the first viewing point is moved toward a backwardportion of the vehicular running direction; display the generateddisplay image; and switching the displayed image from a bird's eye viewimage when the vehicle is moving in a forward direction, to a top viewimage when the vehicle is moving in a backward direction.
 17. An imagedisplay apparatus for an automotive vehicle, comprising: a plurality ofcameras disposed to photograph respective fields near the vehicle; avehicular running state obtaining section that obtains a vehicularrunning state; a display image generating section that generates a topview display image looking down a whole part of the vehicle through anapproximately vertical angle from a first viewing point on an upper skyof the vehicle and bird's eye view display images looking down the wholepart of the vehicle through arbitrary looking-down angles and fromarbitrary viewing points at which the first viewing point is movedtoward front and backward portions of a vehicular running direction inaccordance with the vehicular running state; a display sectionconfigured to display one of the images generated by the display imagegenerating section in accordance with the vehicular running state; and adisplay image switching section that switches the displayed image toanother one of the generated display images, wherein the displayed imageis switched from a bird's eye view image when the vehicle is moving in aforward direction, to a top view image when the vehicle is moving in abackward direction.